(From west to east)

• Iris is in the constellation of Cancer.
• Juno is stationary on the 29th in the constellation of Leo.
• Massalia is in the constellation of Leo.
• Hygiea is in the constellation of Libra.
• Vesta is in the constellation of Capricornus.

• Information about the Minor Planets can be found at the Minor Planet Observer website.

"PASADENA, Calif. - Like forensic scientists examining fingerprints at a cosmic crime scene, scientists working with data from NASA's Cassini, Galileo and New Horizons missions have traced telltale ripples in the rings of Saturn and Jupiter back to collisions with cometary fragments dating back more than 10 years ago.

The ripple-producing culprit, in the case of Jupiter, was comet Shoemaker-Levy 9, whose debris cloud hurtled through the thin Jupiter ring system during a kamikaze course into the planet in July 1994. Scientists attribute Saturn's ripples to a similar object - likely another cloud of comet debris -- plunging through the inner rings in the second half of 1983. The findings are detailed in a pair of papers published online today in the journal Science.

"What's cool is we're finding evidence that a planet's rings can be affected by specific, traceable events that happened in the last 30 years, rather than a hundred million years ago," said Matthew Hedman, a Cassini imaging team associate, lead author of one of the papers, and a research associate at Cornell University, Ithaca, N.Y. "The solar system is a much more dynamic place than we gave it credit for."

Cassini Imaging Team

"New Horizons is ready to put another planet - or at least the planet's orbit - in its rearview mirror. The Pluto-bound spacecraft crosses the path of Uranus around 6 p.m. EDT on March 18, more than 1.8 billion miles from Earth.

"New Horizons is all about delayed gratification, and our 9 1/2-year cruise to the Pluto system illustrates that," says Principal Investigator Alan Stern, of the Southwest Research Institute. "Crossing the orbit of Uranus is another milepost along our long journey to the very frontier of exploration."

New Horizons is headed for a rendezvous with planet Pluto and its three moons in July 2015 and, soon after, possible encounters with smaller bodies in the distant Kuiper Belt. The fastest spacecraft ever launched, New Horizons has already covered serious space since lifting off in January 2006 Ñ traversing 20 times the distance between Earth and the sun, including a flight through the Jupiter system in 2007 for a gravity-assisted speed boost and scientific observations of the giant planet and its largest moons."

LORRI Looks Back

New Horizons gallery

"On March 29, 1807, German astronomer Heinrich Wilhelm Olbers spotted Vesta as a pinprick of light in the sky. Two hundred and four years later, as NASA's Dawn spacecraft prepares to begin orbiting this intriguing world, scientists now know how special this world is, even if there has been some debate on how to classify it.

Vesta is most commonly called an asteroid because it lies in the orbiting rubble patch known as the main asteroid belt between Mars and Jupiter. But the vast majority of objects in the main belt are lightweights, 100-kilometers-wide (about 60-miles wide) or smaller, compared with Vesta, which is about 530 kilometers (330 miles) across on average. In fact, numerous bits of Vesta ejected by collisions with other objects have been identified in the main belt.

"I don't think Vesta should be called an asteroid," said Tom McCord, a Dawn co-investigator based at the Bear Fight Institute, Winthrop, Wash. "Not only is Vesta so much larger, but it's an evolved object, unlike most things we call asteroids."

The layered structure of Vesta (core, mantle and crust) is the key trait that makes Vesta more like planets such as Earth, Venus and Mars than the other asteroids, McCord said. Like the planets, Vesta had sufficient radioactive material inside when it coalesced, releasing heat that melted rock and enabled lighter layers to float to the outside. Scientists call this process differentiation."

"MESSENGER has delivered its first image since entering orbit about Mercury on March 17. It was taken today at 5:20 am EDT by the Mercury Dual Imaging System as the spacecraft sailed high above Mercury's south pole, and provides a glimpse of portions of Mercury's surface not previously seen by spacecraft. The image was acquired as part of the orbital commissioning phase of the MESSENGER mission. Continuous global mapping of Mercury will begin on April 4."

"PASADENA, Calif., -- NASA's Mars Odyssey, which launched in 2001, will break the record Wednesday for longest-serving spacecraft at the Red Planet. The probe begins its 3,340th day in Martian orbit at 5:55 p.m. PST (8:55 p.m. EST) on Wednesday to break the record set by NASA's Mars Global Surveyor, which orbited Mars from 1997 to 2006.

Odyssey's longevity enables continued science, including the monitoring of seasonal changes on Mars from year to year and the most detailed maps ever made of most of the planet. In 2002, the spacecraft detected hydrogen just below the surface throughout Mars' high-latitude regions. The deduction that the hydrogen is in frozen water prompted NASA's Phoenix Mars Lander mission, which confirmed the theory in 2008. Odyssey also carried the first experiment sent to Mars specifically to prepare for human missions, and found radiation levels around the planet from solar flares and cosmic rays are two to three times higher than around Earth."

Global Martian Map

"A simulated fly-through using the newly assembled imagery is available online.

The fly-through plus tools for wandering across and zooming into the large image are at THEMIS."

Daily Mars Odyssey THEMIS Images
Can be found at the Thermal Emission Imaging System (THEMIS) website.

The Odyssey data are available through a new online access system established by the Planetary Data System.

SPIRIT UPDATE: Spirit Remains Silent at Troy - sols 2567-2573, March 24-30, 2011:

"No communication has been received from Spirit since Sol 2210 (March 22, 2010).

Deep Space Network X-band listening and recovery commanding continue. The project has been systematically conducting commanding over a range of frequencies and over a range of local solar times on Mars. This covers the possibility that the rover's receiver has degraded and/or the clock has drifted significantly since March of 2010.

The project is continuing the commanding of extra-long ultra-high frequency (UHF) relay passes to account for possible rover clock drift or clock error and to make the rover responsive to UHF relay (if it is has experienced a mission-clock fault). The team is also commanding the backup solid-state power amplifier, in case the primary X-band transmitter has failed.

Total odometry is unchanged at 7,730.50 meters (4.80 miles)."

OPPORTUNITY UPDATE: Opportunity Completes Several Drives This Week - sols 2546-2553, March 23-30, 2011:

"Opportunity has resumed the trek towards Endeavour crater with a series of drives.

On Sol 2547 (March 24, 2011), the rover drove over 100 meters (328 feet) due east away from Santa Maria crater and toward Endeavour. On the next sol, Opportunity completed another long drive of over 114 meters (374 feet), but this time to the south to avoid some boulder-strewn terrain. On Sol 2551 (March 28, 2011), the rover continued in a south-southeast direction with a 71-meter (233 foot) drive to avoid more difficult terrain. Opportunity drove again on Sol 2552 (March 29, 2011), with a 39-meter (128-foot) drive, crossing another odometry mark. Opportunity has now driven over 27 kilometers (almost 17 miles) on Mars!

There has been a small increase in the motor currents for the right-front wheel. The project is keeping a close eye on this. A diagnostic of the miniature thermal emission spectrometer (Mini-TES) instrument was performed on Sol 2550 (March 27, 2011). The result of these tests still indicates anomalous behavior. More testing is planned. As of Sol 2552 (March 29, 2011), solar array energy production was 423 watt-hours with an elevated atmospheric opacity (Tau) of 0.914 and a solar array dust factor of 0.560.

Total odometry is 27,035.63 meters (27 kilometers, or 16.80 miles)."

Landing sites